1. Field of the Invention
The invention is directed to a plastic spring.
2. Description of the Related Art
DE-AS 1 009 500 discloses a hollow suspension body made of rubber or resilient plastic for absorbing shocks in vehicles having a cylindrical hollow body with connections at the ends. These connections at the ends impede an arrangement in which a vibration damper is mounted coaxial to the spring.
GB 698 322 is directed to a hollow suspension body made of rubber which is tensioned axially between two spring plates. A first spring plate is fastened to a cylinder and a second spring plate is fastened to a central rod of the suspension arrangement. The hollow suspension body contacts the piston rod radially so that frictional forces occur between the piston rod and the hollow suspension body with every movement of the suspension.
A spring element for absorbing shocks in vehicle bodies is known from DE 1 655 642 A1. This spring element has a corrugated tube profile and comprises a fiber-reinforced plastic. The spring element is tensioned at the ends to be tight against pressure.
Also noteworthy in this connection is DE 23 40 917 A1 which likewise discloses a spring element made of plastic. However, in contrast to the spring element according to DE 1 655 642, a compressed gas filling is not used, and a simple contact surface on its front is sufficient to assume the supporting load. When the spring element is compressed, the air filling contained in the spring element can be vented by way of at least one opening.
DE 101 44 163 C1 discloses a suspension strut with a spring plate that can be adjusted with respect to height. The spring plate has a sleeve portion arranged in a chamber on the cylinder side. The sleeve portion is displaced axially in the chamber by filling the chamber and the preloading of a helical compression spring. The spring plate is made of a metal material, and the sleeve portion is formed from a plate by deep drawing. Unfortunately, this limits the useful length of the sleeve portion.
Although already known for a long time, the described spring elements in this constructional form have failed to gain acceptance in vehicle engineering.